Korey Kesici, 22, was shot multiple times after he went to speak to men sitting in a stolen white BMW parked outside his home on Bangalore Way, Mickleham about 12.05am on May 5.
Kesici died on the street in front of his parents and sisters.
His sister, Jasmine Kesici, said it has been incredibly difficult.
“I hear gunshots every time I close my eyes and the gut-wrenching screams of my mum,” she said.
Police have ruled his death as a “deliberate, targeted and organised crime hit”.
The BMW was found on fire in nearby street St Georges Boulevard shortly afterwards.
A stolen red Holden Commodore ute, which was seen driving in convoy with the BMW after the driver stole petrol at a service station on the corner of Main Street and Edgars Road in Thomastown about 11pm on May 4, was then set on fire in Beveridge about 7.30pm on May 6.
Police have spent seven months trying to identify the murderers, having combed through thousands of hours of CCTV footage.
They have now released CCTV of a man seen near Kesici’s house shortly before the shooting, as well as the man who stole petrol for the red Holden, in the hope someone can identify them to police.
The investigation into Kesici’s murder, including the motive, has been complicated by his crime connections, Detective Acting Superintendent Dean Thomas has said.
“We know Korey had connections to a number of organised crime groups, including outlaw motorcycle gangs and other organised crime groups,” he said.
“What is clear to us is that this was a deliberate, targeted organised crime hit. It was more than a simple street exchange. Korey’s murder involved a confronting level of public violence.
“Police ask that people look closely at the footage of the men and the two vehicles and if they have any information that may identify them, to please contact police.”
Police are also keen to speak to anyone who witnessed the incident, as well as anyone in the area between 11pm and 1am and who may have dashcam or CCTV footage of either car or man involved, or anyone who has information on associates of Kesici’s or any motivation for the shooting.
Information can be provided anonymously via CrimeStoppers.